Wheel bearing for a utility vehicle

ABSTRACT

A wheel bearing for a utility vehicle, having a sheath-shaped support shaft in which an axle of the utility vehicle can be concentrically accepted, a wheel hub, and a first roller bearing as well as a second roller bearing for the wheel hub to roll over the support shaft, with the second roller bearing being axially pre-stressed on the sheath-shaped support shaft via a stop, cold-formed from the support shaft, against the first roller bearing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from German Patent Application No. DE 10 2011 076 275.2, filed May 23, 2011 which application is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention relates to a wheel bearing for a utility vehicle, the utility vehicle, and a method for producing the wheel bearing.

BACKGROUND OF THE INVENTION

Wheel bearings are arranged in the center of a wheel and serve in the vehicle for the rotational fastening of the wheel at the vehicle chassis. At the vehicle, the wheel bearing separates rotational components, such as the wheel hub, from fixed components, such as the wheel suspension. The wheel bearing transfers forces and momentums from the road to the undercarriage and vice versa.

BRIEF SUMMARY OF THE INVENTION

One object of the invention is to provide an improved wheel bearing for a vehicle.

The invention suggests providing a wheel bearing of the type mentioned at the outset with a support shaft, in which the axle of the vehicle can be accepted concentrically. The actual roller bearings of the wheel bearing are arranged on the support shaft and axially clamped to each other via a stop cold-formed from the support shaft.

The invention is based on the thought that a wheel bearing could be composed from two individual roller bearings, such as tapered roller bearings, for example, which could be axially arranged distanced from each other radially between an axle and a wheel hub of a vehicle. In this design it would be difficult, though, to keep any lubricant in said roller bearings, so that the roller bearings frequently, usually after a driven distance of 40,000 kilometers would have to be relubricated, which leads to expensive maintenance measures for relubricating such roller bearings. Additionally, the roller bearings are subject to increased soiling and wear and tear, which could lead to increased fuel consumption, for example. Ultimately, in such roller bearings the pre-stressing at such wheel bearings cannot be adjusted in order to reduce any axial play and thus keep it steady over an extended life span. Here, pre-stressing relates to a force by which the exterior rings of the individual roller bearings axially press against the interior rings of the roller bearings, so that the roller elements are clamped between the exterior rings and the interior rings.

However, the wheel bearings could also be produced as a closed unit, with the individual wheel bearing elements, such as roller elements, lubricant, and wheel hub being connected to each other right from the start, oriented on the life span of the wheel bearing. These wheel bearings are for example known under the names Insert Bearing, Wheel Bearing IT Generation, Trailer Axle Module (TAM), or Front Axle Module (VAM). The production of such wheel bearings may be more expensive by up to 150%, though, than the production of the wheel bearing variants mentioned first.

The invention is based on the idea that a wheel bearing produced as a closed unit could also be produced from two individual roller bearings. This is achieved by the support shaft mentioned at the outset, on which the two roller bearings are axially clamped to each other. Accordingly, the invention provides a wheel bearing for a utility vehicle which includes a sheath-shaped support shaft, in which an axle of the utility vehicle can be accepted concentrically, a wheel hub, a first roller bearing, and a second roller bearing for rolling the wheel hub in reference to the support shaft. The second roller bearing is clamped here on the sheath-shaped support shaft via a stop, cold-formed from the support shaft, axially fixed in reference to the first roller bearing.

By the support shaft and the roller bearing axially clamped on the support shaft, all elements of a wheel bearing can be prefabricated with cost-effectively produced roller bearings and installed in the utility vehicle. Contrary to the wheel bearing designed as a unit, individual elements of the wheel bearing provided can be exchanged, for example, for maintenance purposes when the wheel bearing provided fails, for example, due to signs of overload. It is not required for such an exchange to occur at the utility vehicle itself, but rather it can be done after disassembly of the entire wheel bearing in an environment especially provided for this purpose, such as a shop table. If the wheel bearing provided shall be exchanged for a new wheel bearing, at least the components of the wheel bearing still functioning can be reused, here. By the wheel bearing provided, not only the costs for maintenance of a wheel bearing can be reduced, but due to its design as a functional unit the wheel bearing provided can also be installed with little technical expense, in spite of the fact that individual components of the wheel bearing can be exchanged (such as roller bearings) or replaced (such as lubricants) subsequently.

In one embodiment of the invention, the cold-formed stop represents a collar cold-formed from the support shaft. Due to the cold-forming process, the force-path progression can be determined during the pre-stressing of the two roller bearings and be compared to a predetermined target value. This way, the production process of a wheel bearing can be reliably monitored and automated, where a fixed, defined pre-stressing can be achieved for the two roller bearings, in which the axial air between the two roller bearings is reduced to zero so that the exterior forces acting upon the wheel bearing are distributed over as many roller elements as possible, in the ideal case over all of them.

In another embodiment of the invention, the cold-formed collar is formed by roller rivets at an axial end of the sheath-shaped support shaft. Using the roller rivets, a controllable, well-known deformation process can be used for the cold-forming.

Although the first roller bearing can be fixated on the support shaft such that an interior ring of the roller bearing cannot be distorted in reference to the support shaft, in a further development of the invention, the wheel bearing provided includes another axial stop for the axial counter-bearing of the first roller bearing on the support shaft. For example, the interior ring of the first roller bearing is countered at another axial stop. By the axial stop the two roller bearings can simply be pushed upon the support shaft and by the cold-formed collar clamped to each other, and thus, axially fixated on the support shaft.

In yet another embodiment, the wheel bearing provided includes a spacer sheath supported concentrically on the support shaft, which is arranged axially between an interior ring of the first roller bearing and an interior ring of the second roller bearing and transfers at least a portion of the clamping force from the second roller bearing to the first roller bearing. By the spacer sheath the interior rings of the two roller bearings can be axially clamped to each other in a fixed manner and thus fixated at the support shaft of the wheel bearing provided. Here it is not only possible for the two roller bearings to be pre-stressed in a precisely defined fashion, but also lastingly secured by the spacer sheaths because a primary part of the axial force, holding the roller bearings on the support sheath, can be compensated by the spacer sheath, with the exterior ring of the roller bearing being required only to contact axially, and thus, allowing a pre-stressing to such an extent as permitted by the axial extension of the spacer sheath.

In another embodiment, a radially inwardly aligned projection follows the wheel hub of the wheel bearing provided, which axially engages between an exterior ring of the first roller bearing and an exterior ring of the second roller bearing and at least transfers a portion of the clamping force from the second roller bearing to the first roller bearing. The pre-stressing can be precisely adjusted in the two roller bearings via the axial extension of this projection.

The roller bearings may represent ball bearings, for example. Preferably, the roller bearings are tapered roller bearings where their tapers as the roller bodies compensate the forces developing over their tapered surface and are thus mechanically particularly resistant.

The tapers of the tapered roller bearings may be arranged in an O-shaped or a tandem arrangement. Preferably, the tapers of the tapered roller bearing may be arranged X-shaped with the tips of the tapers approaching the axis of rotation of the bearing.

The invention also provides for a utility vehicle having a chassis with a fixed axle, a wheel, and a wheel bearing provided to support the wheel at the rigid axle.

The invention also provides for a method for producing a wheel bearing for a utility vehicle, which includes the steps axially supporting a first roller bearing on a sheath-shaped support shaft, in which an axle of the utility vehicle can be accepted in a concentric fashion, radially supporting a wheel hub on the first roller bearing, so that a radial gap develops between the support shaft and the wheel hub, inserting a second roller bearing into the radial gap, and clamping the second roller bearing on the sheath-shaped support shaft in reference to the first roller bearing by way of cold-forming an axial stop from the support shaft. Here, the steps axially supporting the first roller bearing on the sheath-shaped support shaft and radially supporting the wheel hub on the first roller bearing can be performed in any arbitrary sequence.

BRIEF DESCRIPTION OF THE DRAWING

The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which:

FIG. 1 shows an exploded view of a wheel bearing arranged on an axle;

FIG. 2 illustrates a cross-sectional view of the wheel bearing of FIG. 1; and,

FIG. 3 is a perspective view of a detail of the wheel bearing of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention.

While the present invention is described with respect to what is presently considered to be the preferred aspects, it is to be understood that the invention as claimed is not limited to the disclosed aspects.

Furthermore, it is understood that this invention is not limited to the particular methodology, materials and modifications described and, as such, may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described.

Reference is made to FIGS. 1 through 3, which show wheel bearing 2 on an axle 4 of a vehicle, not shown in greater detail.

In one embodiment, axle 4 represents rigid axle 4. In rigid axle 4, wheel hub 6, to be described, of roller bearing 2 is arranged rotational about the rigid axle body of the rigid axle 4. The rigid axles are commonly used in utility vehicles due to their simple and robust design and in rare cases in passenger vehicles, in which usually independent suspension systems are used. Contrary to rigid axle 4, in the independent suspension the wheel hub is connected rotationally fixed to the vehicle chassis.

Wheel bearing 2 includes wheel hub 6, which can be arranged for rotation on support shaft 8. Here, wheel hub 6 is rotationally supported via interior roller bearing 10 and exterior roller bearing 12 on support shaft 8. Here, interior roller bearing 10 represents a roller bearing, which in the assembled state placed upon rigid axle 4 is arranged at the vehicle side, while exterior roller bearing 12 in the assembled state placed upon rigid axle 4 is arranged at the side of wheel bearing 2 facing away from the vehicle.

Each roller bearing 10, 12 includes interior ring 14 and exterior ring 16 rotationally supported in reference to interior ring 14. Roller bodies in the form of tapered rollers 18 are arranged between interior ring 14 and exterior ring 16, over which interior ring 14 can roll in reference to exterior ring 16. Plurality of tapered rollers 18 are arranged between interior rings 14 and exterior rings 16 of two roller bearings 10, 12, of which, for reasons of clarity, in FIGS. 1 through 3 only one of them is provided with a reference character. The use of tapered rollers 18 as roller bodies is preferable in utility vehicles because, compared to spherical roller bearings, they show a greater surface by which loads can be compensated between the utility vehicle and the surface of the road. In principle, depending on the vehicle in which wheel bearings 2 are used, any arbitrary type of roller body can be used, though. Furthermore, tapered rollers 18 in the present embodiment are arranged X-shaped, i.e., the tips of tapered rollers 18 are aligned towards each other and towards axis of rotation 20 of wheel bearing 2. Tapered rollers 18 can further be arranged either O-shaped, with the tips of tapered rollers 18 being aligned towards each other and away from axis of rotation 20 of the wheel bearing, or in a tandem shape, in which tapered rollers 18 are aligned in parallel.

Roller bearings 10, 12 are pushed axially upon support shaft 8 and axially distanced from each other by spacer sheath 22 contacting interior rings 14. Here, support shaft 8 includes axial bearing stop 24, which is embodied at wheel bearing 2 at the vehicle side and axially countered at interior ring 14 of interior roller bearing 10. Collar 26 is embodied at the end of support shaft 8 axially opposite axial bearing stop 24, which axially pushes interior ring 14 of exterior roller bearing 12 against spacer sheath 22, which in turn pushes interior ring 14 of interior roller bearing 10 axially against axial bearing stop 24. This way interior rings 14 of two roller bearings 10, 12 are held on support shaft 8, non-rotationally by collar 26, but at least axially.

Support shaft 8 includes an axial penetration 28 with rigid axle 4 being axially guided through it. In the area of rigid axle 4 passing through axial penetration 28, the axle tapers radially such that rigid axle 4 forms axial shaft stop 30, axially countered by support shaft 8. Using nut 34 screwed on, support shaft 8 can axially be pushed via thread 32, embodied on the axial end of rigid axle 4, against axial shaft stop 30, such that support shaft 8 is held in a non-rotatable fashion, but at least axially, on rigid axle 4.

Wheel hub 6 is placed radially upon exterior rings 16 of roller bearings 10, 12. It includes flange 36 for fastening a brake disk, not shown. Respective fastening bores 38 are embodied on flange 36 for fastening the brake disk. Axially at the face of the side facing away from vehicle additional fastening bores 40 are embodied at wheel hub 6, by which a wheel, not shown, can be fastened to wheel hub 6. Wheel hub 6 is further provided with interior radial projection 42, which interior roller bearing 10 contacts, such that interior roller bearing 10 is axially accepted between bearing stop 24 and interior radial projection 42. In the same fashion, wheel hub 6 shows exterior radial projection 44, which exterior roller bearing 12 contacts, such that it is axially accepted between collar 26 and exterior radial projection 44. Exterior rings 16 of two roller bearings 10, 12 can be axially pressed apart in reference to each other via axial distance 46 of two radial projections 42, 44 such that exterior rings 16 axially press against interior rings 14, due to the fixed axial position of interior rings 14 on support shaft 8, and this way apply a slight pre-stressing upon tapered rollers 18 between interior rings 14 and exterior rings 16. In order to save material, space 48 embodied between two radial projections 42, 44 may remain free from material. In order to prevent any lubricant from entering space 48 from roller bearings 10, 12 protective rings 50 are clamped axially between exterior rings 16 of roller bearings 10, 12 and their respective radial projections 42, 44, which hold the lubricant in roller bearings 10, 12. Casement seal 52 is arranged at the vehicle side radially between wheel hub 6 and bearing stop 24 of support shaft 8, preventing any lubricant from exiting interior roller bearing 10 towards the vehicle side. In the same manner, casement seal 54 facing away from the vehicle is arranged between the exterior ring of exterior roller bearing 12 and wheel hub 6 preventing any lubricant from exiting the side of wheel bearing 6 at the side facing away from the vehicle.

In wheel bearing 2 shown, interior rings 14 of roller bearings 10, 12 can be held with a high clamping force on support shaft 8 in an axially fixed manner via the spacer sheath 22. Opposite thereto, by a precise sizing of two radial projections 42, 44 and their axial distance 46, the pressure of exterior rings 16 against their respective interior rings 14 can be precisely defined and lastingly upheld such that a precise pre-stress can be adjusted in roller bearings 10, 12. The pre-stress can already be adjusted during manufacturing and/or assembly of wheel bearing 2, and thus, it is not necessary to adjust it during the placement of the individual wheel bearing components on rigid axle 4 of the vehicle.

In order to protect the area of rigid axle 4 accepted in support shaft 8, for example, from penetrating liquids, O-rings 56 are arranged on rigid axle 4, which seal the area of fixed axles 4 in the area accepted in the support shaft from the environment.

In order to produce wheel bearing 2, first support shaft 8 is provided with axial bearing stop 24 and the axial penetration. For collar 16 to be produced later, the end of support shaft 8 opposite axial bearing stop 24 is axially embodied with such a length that this end axially projects from wheel hub 6 when wheel hub 6 is accepted. Subsequently, one of protective rings 50, interior roller bearing 10, and casement seal 52 are inserted into the opening of wheel hub 6 facing the vehicle and pushed together with wheel hub 6 along support shaft 8 until interior roller bearing 10 on the one side contacts axial bearing stop 24 as well as interior radial projection 42. In the next step, spacer sheath 22 is pushed axially along support shaft 8 until it axially contacts interior ring 14 of interior roller bearing 10. Then, other protective ring 50 and exterior roller bearing 12 are axially pushed along support shaft 8 until interior ring 14 of exterior roller bearing 12 contacts spacer sheath 22. Finally, collar 26 is produced by cold-forming the above-mentioned projecting axial end of support shaft 8. For this purpose, the projecting axial end of support shaft 8 can preferably be riveted.

In order to connect finished wheel bearing 2 with rigid axle 4, first O-rings 56 are placed upon rigid axle 4 and then the wheel bearing is pushed axially over rigid axle 4 until wheel bearing 2 axially contacts shaft stop 30. Finally, wheel bearing 2 is axially fixated on rigid axle 4 via nut 34.

Thus, it is seen that the objects of the present invention are efficiently obtained, although modifications and changes to the invention should be readily apparent to those having ordinary skill in the art, which modifications are intended to be within the spirit and scope of the invention as claimed. It also is understood that the foregoing description is illustrative of the present invention and should not be considered as limiting. Therefore, other embodiments of the present invention are possible without departing from the spirit and scope of the present invention.

LIST OF REFERENCE NUMBERS

-   2 Wheel bearing -   4 Rigid axle -   6 Wheel hub -   8 Support shaft -   10 Roller bearing -   12 Roller bearing -   14 Interior ring -   16 Exterior ring -   18 Tapered rollers -   20 Axis of rotation -   22 Spacer sheath -   24 Bearing stop -   26 Collar -   28 Penetration -   30 Shaft stop -   32 Thread -   34 Nut -   36 Flange -   38 Fastening bore -   40 Fastening bore -   42 Radial projection -   44 Radial projection -   48 Space -   50 Protective ring -   52 Casement seal -   54 Casement seal -   56 O-ring 

1. A wheel bearing for a utility vehicle, comprising: a sheath-shaped support shaft in which an axle of the utility vehicle can be concentrically accepted; a wheel hub; and, a first roller bearing as well as a second roller bearing to roll the wheel hub in reference to the support shaft, wherein the second roller bearing is axially pre-stressed against the first roller bearing on the sheath-shaped support shaft via a stop cold-formed from the support shaft.
 2. The wheel bearing as recited in claim 1, with the cold-formed stop representing a collar cold-formed from the support shaft.
 3. The wheel bearing as recited in claim 2, with the cold-formed collar being formed by roller riveting an axial end of the sheath-shaped support shaft.
 4. The wheel bearing as recited in claim 1, further comprising another axial stop for the axial countering of the first roller bearing on the support shaft.
 5. The wheel bearing as recited in claim 1, further comprising a spacer sheath concentrically supported in the support shaft, which is arranged axially between an interior ring of the first roller bearing and an interior ring of the second roller bearing, and which transfers at least a portion of the clamping force from the second roller bearing to the first roller bearing.
 6. The wheel bearing as recited in claim 1, with the wheel hub comprising a projection aligned radially inwardly, which axially engages between an exterior ring of the first roller bearing and an exterior ring of the second roller bearing and which transfers at least a portion of the clamping force from the second roller bearing to the first roller bearing.
 7. The wheel bearing as recited in claim 1, with the roller bearing being tapered roller bearings
 8. The wheel bearing as recited in claim 4, with the tapered roller bearings being arranged in an X-shape.
 9. A utility vehicle comprising: a chassis with a rigid axle; a wheel; and, a wheel bearing comprising, a sheath-shaped support shaft in which an axle of the utility vehicle can be concentrically accepted; a wheel hub; and, a first roller bearing as well as a second roller bearing to roll the wheel hub in reference to the support shaft, wherein the second roller bearing is axially pre-stressed against the first roller bearing on the sheath-shaped support shaft via a stop cold-formed from the support shaft, wherein the wheel bearing supports the wheel on the rigid axle.
 10. A method for producing a wheel bearing for a utility vehicle, comprising: axially supporting a first roller bearing on a sheath-shaped support shaft, in which an axle of the utility vehicle can be concentrically accepted; radially supporting a wheel hub on the first roller bearing such that a radial gap is formed between the support shaft and the wheel hub; inserting a second roller bearing into the radial gap; and, clamping the second roller bearing on the sheath-shaped support shaft against the first roller bearing by cold-forming an axial stop from the support shaft. 